FDR Data: Enhancement to the NATS Wake Turbulence Database

Transcription

1 FDR Data: Enhancement to the NATS Wake Turbulence Database Dr. Deborah Rushton WakeNet EU 2014 Workshop 14 th May

2 Contents Introduction NATS Wake Turbulence Database Limitations of voluntary reporting scheme Proposed enhancement to Wake Turbulence Database Proposed use of FDR data for objective Wake Turbulence Encounter assessment

3 Introduction Time Based Separation (TBS) due to be applied at Heathrow in May TBS applied across all headwind conditions on final approach. TBS will rebalance Wake Turbulence Encounter (WTE) risk across different wind conditions. Operational monitoring of TBS requires comparison of WTE reporting rate for pre- and post- TBS implementation

4 Wake Turbulence Database Voluntary UK WTE reporting scheme established in Used to understand operational conditions that result in a WTE and the effect of a WTE on an aircraft. Used to monitor the effectiveness of current separation minima and procedures. Indicates aircraft types that induce/susceptible to significantly higher WTE rates than others. All WTEs stored on NATS Wake Turbulence Encounter Database WTEs reported to date (~240 per year)

5 NATS Wake Turbulence Encounter reporting process

6 Uses of database Heathrow TC Approach Safety Monitoring Reports to ATC units Specific requests Aircraft types Airlines En-route A380 B748/B787 Introduction of new aircraft types/wt categories Pre- and postoperational concept analysis RVSM TBS

7 Limitations of voluntary reporting scheme Voluntary scheme relies on pilot s judgement recognising WTE. Relies on pilot cooperation completing reports. Expect that the more severe WTEs are reported. Subjective nature of reporting: Pilot recall of event. Interpretation of effect on aircraft. Missing reports/key information. Influenced by safety reporting culture

8 Effect of pilot reporting culture Pilot reporting culture = Likelihood of pilot reporting a WTE. Wake Turbulence reporting scheme is voluntary reporting rate subject to variation. More difficult to quantify than effects from wind, aircraft trajectories, etc. Reporting culture linked to safety awareness campaigns launched when new operating procedures and aircraft types introduced. No. of reported encounters RVSM Year

9 Proposed enhancement to WTE reporting Flight Data Recorder (FDR) data to supplement pilot and ATC WTE reports. Can be used to objectively assess effect of WTE on aircraft. Letter requesting FDR data sent to airlines in January FDR data requested for 5 minutes before and after WTE. Data must include: Time Altitude Roll angle Also useful: Pitch Speed Wind conditions FDR data received from three airlines and promised from other airlines (subject to NDA, etc).

10 WTE detection from FDR data Baseleg to intercept Capture of localiser Encounter Pilot corrective action

11 WTE detection from FDR data Turn onto baseleg Baseleg to intercept Capture of localiser

12 Proposed use of FDR data for objective WTE assessment FDR data provides objective means for assessing the effect of WTE on the aircraft. Contains information about deviations to aircraft attitude and trajectory during WTE. Challenge to find appropriate and meaningful measure of effect on the aircraft. Must be easily derived from parameters in FDR data

13 Proposed use of FDR data for objective WTE assessment Initial analysis will focus on comparing distributions of WTE rollrate pre- and post-tbs implementation Propose to split data into altitude and wind bands (subject to FDR data sample size). Will split data into WTEs where: 1. TBS distance separation DBS distance separation 2. TBS distance separation < DBS distance separation Will provide indication of reporting culture effect

14 Potential reporting scenarios following TBS implementation Scenario 1 Probability of WTE remains the same, but percentage of reported WTEs increases

15 Potential reporting scenarios following TBS implementation Scenario 2 Probability of WTE increases, but percentage of reported WTEs remains the same

16 Potential reporting scenarios following TBS implementation Scenario 3 Probability of WTE increases and percentage of reported WTEs increases

17 Conclusions Wake Turbulence Database important dataset for TBS operational monitoring. Data is subjective and dependent on pilot reporting behaviour. FDR data provides valuable objective viewpoint about effect of WTE on aircraft. Positive response from airlines. FDR data will be used in the comparative assessment of WTE induced roll-rate pre- and post-tbs implementation. Investigating suitability of other metrics easily derived from FDR data

18 Questions?